Algorithms¶

For a list of supported algorithms, see crypto(7) and crypto(9).

IOCTL Request Descriptions¶

CRIOGET int *fd

Clone the fd argument to ioctl(2), yielding a new file descriptor for the creation of sessions.

CIOCFINDDEV struct crypt_find_op *fop

struct crypt_find_op {
    int     crid;       /* driver id + flags */
    char    name[32];   /* device/driver name */
};

    

If crid is -1, then find the driver named name and return the id in crid. If crid is not -1, return the name of the driver with crid in name. In either case, if the driver is not found, ENOENT is returned.

CIOCGSESSION struct session_op *sessp

struct session_op {
    u_int32_t cipher;	/* e.g. CRYPTO_DES_CBC */
    u_int32_t mac;	/* e.g. CRYPTO_MD5_HMAC */

    u_int32_t keylen;	/* cipher key */
    void * key;
    int mackeylen;	/* mac key */
    void * mackey;

    u_int32_t ses;	/* returns: ses # */
};

    

Create a new cryptographic session on a file descriptor for the device; that is, a persistent object specific to the chosen privacy algorithm, integrity algorithm, and keys specified in sessp. The special value 0 for either privacy or integrity is reserved to indicate that the indicated operation (privacy or integrity) is not desired for this session.

Multiple sessions may be bound to a single file descriptor. The session ID returned in sessp->ses is supplied as a required field in the symmetric-operation structure crypt_op for future encryption or hashing requests.

For non-zero symmetric-key privacy algorithms, the privacy algorithm must be specified in sessp->cipher, the key length in sessp->keylen, and the key value in the octets addressed by sessp->key.

For keyed one-way hash algorithms, the one-way hash must be specified in sessp->mac, the key length in sessp->mackey, and the key value in the octets addressed by sessp->mackeylen.

Support for a specific combination of fused privacy and integrity-check algorithms depends on whether the underlying hardware supports that combination. Not all combinations are supported by all hardware, even if the hardware supports each operation as a stand-alone non-fused operation.

CIOCCRYPT struct crypt_op *cr_op

struct crypt_op {
    u_int32_t ses;
    u_int16_t op;	/* e.g. COP_ENCRYPT */
    u_int16_t flags;
    u_int len;
    caddr_t src, dst;
    caddr_t mac;		/* must be large enough for result */
    caddr_t iv;
};

    

Request a symmetric-key (or hash) operation. The file descriptor argument to ioctl(2) must have been bound to a valid session. To encrypt, set cr_op->op to COP_ENCRYPT. To decrypt, set cr_op->op to COP_DECRYPT. The field cr_op->len supplies the length of the input buffer; the fields cr_op->src, cr_op->dst, cr_op->mac, cr_op->iv supply the addresses of the input buffer, output buffer, one-way hash, and initialization vector, respectively.

CIOCCRYPTAEAD struct crypt_aead *cr_aead

struct crypt_aead {
    u_int32_t ses;
    u_int16_t op;	/* e.g. COP_ENCRYPT */
    u_int16_t flags;
    u_int len;
    u_int aadlen;
    u_int ivlen;
    caddr_t src, dst;
    caddr_t aad;
    caddr_t tag;		/* must be large enough for result */
    caddr_t iv;
};

    

The CIOCCRYPTAEAD is similar to the CIOCCRYPT but provides additional data in cr_aead->aad to include in the authentication mode.

CIOCFSESSION u_int32_t ses_id

Destroys the /dev/crypto session associated with the file-descriptor argument.

CIOCNFSESSION struct crypt_sfop *sfop;

struct crypt_sfop {
    size_t count;
    u_int32_t *sesid;
};

    

Destroys the sfop->count sessions specified by the sfop array of session identifiers.

Asymmetric-key algorithms¶

Contingent upon hardware support, the following asymmetric (public-key/private-key; or key-exchange subroutine) operations may also be available:

See below for discussion of the input and output parameter counts.

Asymmetric-key commands¶

CIOCASYMFEAT int *feature_mask

Returns a bitmask of supported asymmetric-key operations. Each of the above-listed asymmetric operations is present if and only if the bit position numbered by the code for that operation is set. For example, CRK_MOD_EXP is available if and only if the bit (1 << CRK_MOD_EXP) is set.

CIOCKEY struct crypt_kop *kop

struct crypt_kop {
    u_int crk_op;		/* e.g. CRK_MOD_EXP */
    u_int crk_status;		/* return status */
    u_short crk_iparams;	/* # of input params */
    u_short crk_oparams;	/* # of output params */
    u_int crk_pad1;
    struct crparam crk_param[CRK_MAXPARAM];
};

/* Bignum parameter, in packed bytes. */
struct crparam {
    void * crp_p;
    u_int crp_nbits;
};

    

Performs an asymmetric-key operation from the list above. The specific operation is supplied in kop->crk_op; final status for the operation is returned in kop->crk_status. The number of input arguments and the number of output arguments is specified in kop->crk_iparams and kop->crk_iparams, respectively. The field crk_param[] must be filled in with exactly kop->crk_iparams + kop->crk_oparams arguments, each encoded as a struct crparam (address, bitlength) pair.

The semantics of these arguments are currently undocumented.